This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 104 |
| 2 | 1020 |
| 3 | 6092 |
| 4 | 26670 |
| 5 | 94128 |
| 6 | 283338 |
| 7 | 754380 |
| 8 | 1821534 |
| 9 | 4061200 |